Note 7 - Net Income per Common Share (Details) - Net Income per Common Share Calculation (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net Income per Common Share Calculation [Abstract]
Net income available to common shareholders (in Dollars)	$ 12,802	$ 11,533	$ 25,160	$ 22,964
Average common shares outstanding	25,982	25,742	25,955	25,641
Adjustment for common share equivalents	647	592	645	593
Average common shares outstanding-diluted	26,629	26,334	26,600	26,234
Diluted net income per common share (in Dollars per share)	$ 0.48	$ 0.44	$ 0.95	$ 0.88
Anti-dilutive shares	21,000	95,966	21,000	101,466
Basic net income per common share (in Dollars per share)	$ 0.49	$ 0.45	$ 0.97	$ 0.90